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Diffstat (limited to 'gdb/dummy-frame.c')
| -rw-r--r-- | gdb/dummy-frame.c | 308 |
1 files changed, 308 insertions, 0 deletions
diff --git a/gdb/dummy-frame.c b/gdb/dummy-frame.c new file mode 100644 index 0000000..1a2a315 --- /dev/null +++ b/gdb/dummy-frame.c @@ -0,0 +1,308 @@ +/* Code dealing with dummy stack frames, for GDB, the GNU debugger. + + Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, + 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002 Free Software + Foundation, Inc. + + This file is part of GDB. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + + +#include "defs.h" +#include "dummy-frame.h" +#include "regcache.h" +#include "frame.h" +#include "inferior.h" +#include "gdb_assert.h" + +/* Dummy frame. This saves the processor state just prior to setting + up the inferior function call. Older targets save the registers + on the target stack (but that really slows down function calls). */ + +struct dummy_frame +{ + struct dummy_frame *next; + + CORE_ADDR pc; + CORE_ADDR fp; + CORE_ADDR sp; + CORE_ADDR top; + struct regcache *regcache; + + /* Address range of the call dummy code. Look for PC in the range + [LO..HI) (after allowing for DECR_PC_AFTER_BREAK). */ + CORE_ADDR call_lo; + CORE_ADDR call_hi; +}; + +static struct dummy_frame *dummy_frame_stack = NULL; + +/* Function: find_dummy_frame(pc, fp, sp) + + Search the stack of dummy frames for one matching the given PC and + FP/SP. Unlike PC_IN_CALL_DUMMY, this function doesn't need to + adjust for DECR_PC_AFTER_BREAK. This is because it is only legal + to call this function after the PC has been adjusted. */ + +struct regcache * +generic_find_dummy_frame (CORE_ADDR pc, CORE_ADDR fp) +{ + struct dummy_frame *dummyframe; + + for (dummyframe = dummy_frame_stack; dummyframe != NULL; + dummyframe = dummyframe->next) + { + /* Does the PC fall within the dummy frame's breakpoint + instruction. If not, discard this one. */ + if (!(pc >= dummyframe->call_lo && pc < dummyframe->call_hi)) + continue; + /* Does the FP match? */ + if (dummyframe->top != 0) + { + /* If the target architecture explicitly saved the + top-of-stack before the inferior function call, assume + that that same architecture will always pass in an FP + (frame base) value that eactly matches that saved TOS. + Don't check the saved SP and SP as they can lead to false + hits. */ + if (fp != dummyframe->top) + continue; + } + else + { + /* An older target that hasn't explicitly or implicitly + saved the dummy frame's top-of-stack. Try matching the + FP against the saved SP and FP. NOTE: If you're trying + to fix a problem with GDB not correctly finding a dummy + frame, check the comments that go with FRAME_ALIGN() and + SAVE_DUMMY_FRAME_TOS(). */ + if (fp != dummyframe->fp && fp != dummyframe->sp) + continue; + } + /* The FP matches this dummy frame. */ + return dummyframe->regcache; + } + + return 0; +} + +char * +deprecated_generic_find_dummy_frame (CORE_ADDR pc, CORE_ADDR fp) +{ + struct regcache *regcache = generic_find_dummy_frame (pc, fp); + if (regcache == NULL) + return NULL; + return deprecated_grub_regcache_for_registers (regcache); +} + +/* Function: pc_in_call_dummy (pc, sp, fp) + + Return true if the PC falls in a dummy frame created by gdb for an + inferior call. The code below which allows DECR_PC_AFTER_BREAK is + for infrun.c, which may give the function a PC without that + subtracted out. */ + +int +generic_pc_in_call_dummy (CORE_ADDR pc, CORE_ADDR sp, CORE_ADDR fp) +{ + struct dummy_frame *dummyframe; + for (dummyframe = dummy_frame_stack; + dummyframe != NULL; + dummyframe = dummyframe->next) + { + if ((pc >= dummyframe->call_lo) + && (pc < dummyframe->call_hi + DECR_PC_AFTER_BREAK)) + return 1; + } + return 0; +} + +/* Function: read_register_dummy + Find a saved register from before GDB calls a function in the inferior */ + +CORE_ADDR +deprecated_read_register_dummy (CORE_ADDR pc, CORE_ADDR fp, int regno) +{ + struct regcache *dummy_regs = generic_find_dummy_frame (pc, fp); + + if (dummy_regs) + { + /* NOTE: cagney/2002-08-12: Replaced a call to + regcache_raw_read_as_address() with a call to + regcache_cooked_read_unsigned(). The old, ...as_address + function was eventually calling extract_unsigned_integer (via + extract_address) to unpack the registers value. The below is + doing an unsigned extract so that it is functionally + equivalent. The read needs to be cooked as, otherwise, it + will never correctly return the value of a register in the + [NUM_REGS .. NUM_REGS+NUM_PSEUDO_REGS) range. */ + ULONGEST val; + regcache_cooked_read_unsigned (dummy_regs, regno, &val); + return val; + } + else + return 0; +} + +/* Save all the registers on the dummy frame stack. Most ports save the + registers on the target stack. This results in lots of unnecessary memory + references, which are slow when debugging via a serial line. Instead, we + save all the registers internally, and never write them to the stack. The + registers get restored when the called function returns to the entry point, + where a breakpoint is laying in wait. */ + +void +generic_push_dummy_frame (void) +{ + struct dummy_frame *dummy_frame; + CORE_ADDR fp = (get_current_frame ())->frame; + + /* check to see if there are stale dummy frames, + perhaps left over from when a longjump took us out of a + function that was called by the debugger */ + + dummy_frame = dummy_frame_stack; + while (dummy_frame) + if (INNER_THAN (dummy_frame->fp, fp)) /* stale -- destroy! */ + { + dummy_frame_stack = dummy_frame->next; + regcache_xfree (dummy_frame->regcache); + xfree (dummy_frame); + dummy_frame = dummy_frame_stack; + } + else + dummy_frame = dummy_frame->next; + + dummy_frame = xmalloc (sizeof (struct dummy_frame)); + dummy_frame->regcache = regcache_xmalloc (current_gdbarch); + + dummy_frame->pc = read_pc (); + dummy_frame->sp = read_sp (); + dummy_frame->top = 0; + dummy_frame->fp = fp; + regcache_cpy (dummy_frame->regcache, current_regcache); + dummy_frame->next = dummy_frame_stack; + dummy_frame_stack = dummy_frame; +} + +void +generic_save_dummy_frame_tos (CORE_ADDR sp) +{ + dummy_frame_stack->top = sp; +} + +/* Record the upper/lower bounds on the address of the call dummy. */ + +void +generic_save_call_dummy_addr (CORE_ADDR lo, CORE_ADDR hi) +{ + dummy_frame_stack->call_lo = lo; + dummy_frame_stack->call_hi = hi; +} + +/* Restore the machine state from either the saved dummy stack or a + real stack frame. */ + +void +generic_pop_current_frame (void (*popper) (struct frame_info * frame)) +{ + struct frame_info *frame = get_current_frame (); + + if (PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame)) + generic_pop_dummy_frame (); + else + (*popper) (frame); +} + +/* Function: pop_dummy_frame + Restore the machine state from a saved dummy stack frame. */ + +void +generic_pop_dummy_frame (void) +{ + struct dummy_frame *dummy_frame = dummy_frame_stack; + + /* FIXME: what if the first frame isn't the right one, eg.. + because one call-by-hand function has done a longjmp into another one? */ + + if (!dummy_frame) + error ("Can't pop dummy frame!"); + dummy_frame_stack = dummy_frame->next; + regcache_cpy (current_regcache, dummy_frame->regcache); + flush_cached_frames (); + + regcache_xfree (dummy_frame->regcache); + xfree (dummy_frame); +} + +/* Function: fix_call_dummy + Stub function. Generic dummy frames typically do not need to fix + the frame being created */ + +void +generic_fix_call_dummy (char *dummy, CORE_ADDR pc, CORE_ADDR fun, int nargs, + struct value **args, struct type *type, int gcc_p) +{ + return; +} + +/* Given a call-dummy dummy-frame, return the registers. Here the + register value is taken from the local copy of the register buffer. */ + +void +generic_call_dummy_register_unwind (struct frame_info *frame, void **cache, + int regnum, int *optimized, + enum lval_type *lvalp, CORE_ADDR *addrp, + int *realnum, void *bufferp) +{ + gdb_assert (frame != NULL); + gdb_assert (PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame)); + + /* Describe the register's location. Generic dummy frames always + have the register value in an ``expression''. */ + *optimized = 0; + *lvalp = not_lval; + *addrp = 0; + *realnum = -1; + + /* If needed, find and return the value of the register. */ + if (bufferp != NULL) + { + struct regcache *registers; +#if 1 + /* Get the address of the register buffer that contains all the + saved registers for this dummy frame. Cache that address. */ + registers = (*cache); + if (registers == NULL) + { + registers = generic_find_dummy_frame (frame->pc, frame->frame); + (*cache) = registers; + } +#else + /* Get the address of the register buffer that contains the + saved registers and then extract the value from that. */ + registers = generic_find_dummy_frame (frame->pc, frame->frame); +#endif + gdb_assert (registers != NULL); + /* Return the actual value. */ + /* Use the regcache_cooked_read() method so that it, on the fly, + constructs either a raw or pseudo register from the raw + register cache. */ + regcache_cooked_read (registers, regnum, bufferp); + } +} + |